In cellular heterogeneous networks with 2G, 3G and 4G cells, neighboring cell information for handover processes is stored and maintained in neighbor relation tables (NRTs). Automatic neighbor relation (ANR) functions automate the management and optimization of the NRT for each cell. An initial NRT can be obtained from centralized self-organized network (SON) element manager (EM) or network manager (NM), or alternatively a base station (e.g. an eNodeB) may create the initial NRT for itself utilizing the network listening mode. Once the base station is in operation, the NRT is continuously updated based on UE measurements from handover activities.
Geographically predicted NRTs generally have incorrectly prioritized neighbor lists because of differences in the actual RF propagation environment compared to the predicted environment. Additionally, networks continually evolve with the addition of new cells including both small and large area cells due to operations such as cell splitting. For these reasons ongoing optimization of NRTs via SON automated functions is used for heterogeneous networks (HetNets).
In the past, operators have deployed base stations from different vendors in geographically separated areas. Cross-vendor neighbor list optimization is therefore employed at the boundary of network areas. This has conventionally involved manual steps because ANR solutions have operated against network equipment from a single vendor. However, as the network deployments evolve to heterogeneous networks encompassing small cells and macro cells in the same network area, operators can benefit from solutions for maintaining optimized neighbor relations between base stations from different vendors throughout the network area.